


You Pretend That The Bloodstains One Day Will Dry

by PandoraTheExplorer



Category: Undertale (Video Game)
Genre: Angst, Genocide Route Undyne | Undyne the Undying (Undertale), Hurt/Comfort, Sad Ending, Undertale Genocide Route, asgore is undyne's dad, dying dramatically, fellas is it friendly to fly your bffs dying girlfriend halfway across town to her dads house, let's be real guys undyne is a zombie at this point, mettaton third wheels, the effects of determination, undyne kills the human
Language: English
Status: Completed
Published: 2020-12-29
Updated: 2020-12-29
Packaged: 2021-03-10 21:40:33
Rating: Teen And Up Audiences
Warnings: Graphic Depictions Of Violence, Major Character Death
Chapters: 1
Words: 4,153
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/28414047
Author URL: https://archiveofourown.org/users/PandoraTheExplorer/pseuds/PandoraTheExplorer
Summary: Undyne the Undying had, against all odds, defeated the human that had slaughtered half the Underground. And now, with the begrudgingly accepted help of a glamorous robot, it's a race against time to get herself to a healer before her body melts away to nothing. Meanwhile, Undyne can't shake the feeling that, unless they get the human's soul to Asgore soon, everything will be undone.Alphys istoogood at evacuating.
Relationships: Alphys & Mettaton (Undertale), Alphys/Undyne (Undertale), Asgore Dreemurr & Undyne, Mettaton & Undyne (Undertale), Sans & Undyne (Undertale)
Comments: 3
Kudos: 7





	You Pretend That The Bloodstains One Day Will Dry

**Author's Note:**

> I had a bout of inspiration at 5am yesterday and wrote all of this out in like 7 hours yesterday. I edited the hell out of it this morning but I might come back to edit it some more if I decide it's too convoluted later. Guess who's going through their second Undertale phase? If this keeps happening, I might even repost the 30+ chapter Monster-Human War fic I put on Fanfiction.net in middle school. (Edited, of course.) If anyone's interested hmu.
> 
> But yeah. Local fish literally too angry to die. For a while, at least:

The human blocked and dove past endless circles of spears in an intricate dance. If she didn’t know better, Undyne would even say that the human had seen her attacks before. Nevertheless, she persisted.

The human was good, but even they couldn’t dodge forever. They edged out of the paths of two intersecting spears, only to crash into the shaft of a third when they skidded further than they should have on the slippery boards of the bridge. The human gasped in pain and momentarily stopped in their tracks.

Undyne took that opportunity to bombard them with all her fury. Rings of spears twirled around the human and tightened before they could step out of the way. Circles of blinding light appeared under the human’s feet and burst through the bridge as a hailstorm of spears rained upon them. Before they could recover, Undyne waved her arm, turning the human’s soul green and rooting them in place. Volley after volleys of arrows she shot, all of them blocked. 

On their turn, the human gave Undyne a chilling grin. It wasn’t long now; those glowing red eyes seemed to tell her. Undyne didn’t have a lot of HP left, and she doubted the human did, either. Within the next few turns, they both knew, someone would die. 

Undyne remembered the bunny-shaped pastry the human had wolfed down in a previous turn. Out of the two of them, only one had thought to bring any food. On the human’s turn, Undyne could only watch as the human’s hand rummaged through their pockets.

Then the human pulled out something that, Undyne realized later, would be their fatal undoing.

Instead of food, the human retrieved their dust-covered notebook that had dealt Undyne so much damage this battle. And, giving her one last deathly sweet smile, they lunged.

Burning, searing pain spread across Undyne’s chest where she’d been hit, a pain hotter than the rivers of lava in Hotland and the reactors in the Core. Undyne reeled, falling onto one knee. Every speck of magic in her body wanted to give up. Her forehead was dripping with something.

She remembered warm, furry fingers covering her tiny webbed ones, showing her the proper way to grip a spear. She remembered tails thumping on fresh snow at the scratching behind excited, twitching ears. She remembered the roar of fire as a pot of spaghetti, over howling laughter, was pummeled endlessly by spears and bones.

Undyne remembered the rush of falling water. The passionate rambles she had looked upon in awe. The glint of glasses off of the glow of a monitor, accompanied by a shy smile.

She was filled with DETERMINATION.

Ignoring the pain, Undyne held out her hand. A shaft of blue light flickered in it before taking its form. Using the spear, she pulled herself up and swung it in a clean arc in one fluid movement. Aiming the point at her enemy, she finally risked a glance at their face.

The human wasn’t smiling anymore.

The human continued to block her spears with the shield of energy emitted by their soul. They were both going to wear themselves out, one way or another. Undyne tried to steady her labored breaths as she shot more arrows, but eventually, her final volley of arrows narrowed into a single trickle, all coming from one direction.

The human adjusted their shield to block the last of the arrows before giving Undyne that cruel smile again. Undyne’s turn was almost over. If the human could land any hit at all in the next turn, she would collapse into a pile of dust and they could continue on their rampage. The human knew this and leered at her in confidence.

So much confidence, in fact, that they missed the yellow arrow tightly tucked between two white ones.

She could see the human’s eyes shift for a moment as the yellow arrow wove around their body. The human lifted their arm to redirect the shield to block it, but it was too late.

The arrow buried itself into the human’s back, and gone was their final HP.

The body unceremoniously flopped onto the bridge, red liquid oozing from the many wounds acquired in the fight. A glowing heart, almost bursting with streams of mesmerizing red energy, emerged from the body and suspended itself at the height of Undyne’s waist.

Carefully, Undyne edged towards the soul, ignoring the pain in her legs that spiked with every step. Was this what had controlled this vessel of destruction? Was this what had ended the lives of so many monsters?

She reached out to take the soul but recoiled when she glanced down at what remained of its previous owner. The attacks that gave the human its wounds had long since vanished, leaving only a mangled corpse behind. Undyne had never seen a dead being before that maintained its form in life. The small body looked…pitiful. She had killed a child.

Undyne gritted her teeth and reached out for the soul again. The little monster that this human tried to kill had been a child, too.

She couldn’t feel the soul through her gloves-she wondered if souls were even tangible objects at all. Yet it followed the movement of her hand as if she was holding it. Gingerly as to not accidentally absorb the soul, Undyne picked around the human’s body and staggered towards Hotland.

~

The heat of lava under the bridge was scorching. Undyne’s vision swam. She wanted to take off her armor, but she had the feeling that if she stopped for even a second, she would collapse and lose the will to get back up.

But she was so tired. And even though her skin wouldn’t stop dripping with…something, she felt drier than she thought she could take. The human was already dead, she decided. Perhaps it would be fine to just lie down here and rest for a bit. And in a few hours when Alphys or whatever other brave monster ventures out to this bridge, they will be able to collect her dust and bring the soul to Asgore.

She saw, in her mind, the soul suspended just above her head as she lay on Hotland’s bridge, tendrils of red energy flashing around her. And as she saw her own hand reach out for the soul, she could see the flashes getting brighter and brighter until she could see nothing at all, and then the world would stutter back to that fateful moment in Waterfall.

Undyne quickened her pace. The human was dead. There was no way the scenario she imagined was anything more than a delusional fantasy. Yet when she thought about leaving the soul there, she couldn’t rid herself of that sinking dread as the scene flashed through her head again.

She stumbled to the water cooler and spared the time to pour a cup of water on herself before rushing to Alphys’s lab with renewed vigor. Here. If Alphys was still at the lab, she could take the soul to Asgore and Undyne could rest easy.

“OH, THERE YOU ARE.”

Goddammit.

“YOU UGLY LITTLE CREATU-Undyne?”

Against her orders, Undyne’s knees buckled and she found herself sprawled on the floor of the lab, the soul hovering over her head and Mettaton’s stupid LED face flashing in her own in a panic.

“The human is dead,” she slurred, prompting a soft “Oh my stars” from the robot. “Mettaton, you need to get this soul to Asgore. Quick.”

At that, Mettaton darted around the lab, scrambling up the escalator to Alphys’s room. Undyne groaned over the noise of the robot rummaging through his creator’s workbench. “Didn’t you hear what I said?” she called, disliking how weak her voice had become, “Take the goddamn soul!”

Mettaton returned with what looked like a plastic lunchbox and a thermos. “You can’t just handle a human soul with your bare hands,” he proclaimed, guiding the floating heart into the lunchbox and snapping the lid closed. “How did you not accidentally absorb it?”

“I was wearing gloves!” Undyne retorted. She hissed in pain as Mettaton turned her over to lay her on her back. Upon seeing the mangled mess that was her front side, the lights on Mettaton’s display panel flashed even faster. Surprised, Undyne recognized the expression as concern.

“Forget about me!” she said as Mettaton propped her into a sitting position with one hand and offered her the thermos with the other. “The soul, Mettaton. Get it to Asgore.”

“Dear, do you really think I’m so heartless to leave someone to die?” Mettaton asked, setting the thermos in Undyne’s lap and reaching into one of the panels on his body. “This will keep your HP up until we can get you to a hospital,” he said, setting a Mettaton-shaped straw into the thermos, “Drink it. The soul can wait until Alphys gets back. I’ll try to call her.”

With all her might, Undyne turned her head from where the straw poked her cheek. “We can’t wait that long!” she insisted, “You have-“ she paused to gasp for breath, “-you have to get the soul to Asgore NOW!”

A question mark briefly flashed on Mettaton’s display panel, but a metallic huff told Undyne that he, by some miracle, was convinced. Mettaton placed the soul, weighed down by its container, into a compartment in his body, and scooped Undyne into his arms, careful not to spill the contents of the thermos.

“Well, if you’re going to be so annoying about it,” he grumbled as they rolled out of the door of the lab. “Keep drinking that. I’m dropping you off at the nearest hospital.” From the corner of her eye, Undyne could see fire sputter from where Mettaton’s leg once was as they ascended to the sky. “And don’t get your weird goop on my chassis. I just had it polished.”

~

“Darling, would you stop losing HP?” Mettaton said with an edge to his voice. He had been less chatty than Undyne had feared for the trip, only acknowledging Undyne every few minutes to make sure she hasn’t blacked out from pain or to poke her awake if she had.

Undyne hummed weakly. The thermos, which she discovered held some kind of soup, had long since been emptied. She thought she accidentally dropped it over some lava river earlier, though neither she nor Mettaton noticed when it happened.

Now her face was covered in electrodes connected to some sort of device from yet another panel that opened from Mettaton’s body. He said it was some kind of thing to monitor her condition. Undyne failed to see the use in it, since she would eventually crumble to dust anyway, regardless of whether or not Mettaton knew when it would be.

She glanced back at Mettaton, who had fallen silent again. Judging by the lights cycling on his display panel, she would guess he was trying to connect to something, although she wasn’t sure what.

“Does your armor have to be so heavy?” Mettaton asked after a few more minutes of silence. He’d tried to pry off a piece of her armor earlier but stopped when Undyne started screaming in pain.

“If I’m slowing you down,” Undyne murmured, too tired to open her eyes, “just drop me off and go find Asgore on your own.”

“And listen to Alphys cry until the war is done?” Mettaton scoffed, sounding relieved that Undyne hadn’t died yet, “Please, darling, I’ll take the extra hundred pounds.”

~

After that, Undyne swam in and out of consciousness, briefly waking to grumble at Mettaton’s quips and drifting off just as quickly. Then, through the dark haze, she heard a name through the fog that beckoned her.

“Alphys,” Mettaton said, his voice tense, “You need to talk to her. She’s giving up.”

“Undyne?” Undyne winced as Alphys’s terrified voice called through the speaker on Mettaton’s front that her cheek was pressed against. “Undyne, can you hear me?”

“Alphy?” Undyne said softly. For a moment, she was worried that Alphys couldn’t hear her. Or maybe she was already dead, and her ghost was saying things that no one could hear. But then she felt Mettaton’s grip relax and heard Alphys sigh in relief through the speaker. She wasn’t dead yet, then.

“Y-you’re going to be alright,” Alphys said, her voice sounding thick with tears, “T-the hospitals have all been evacuated so Mettaton is going to take you to Asgore’s to heal you. I’m heading there now. Just-just try to stay conscious, okay? If you-if you want me to stay on the phone w-w-with you-”

“Alphys,” Undyne breathed, “I killed the human.”

“I-I-I know,” Alphys replied, her voice breaking, “M-mettaton already told me what happened. You’re amazing, Undyne. You s-saved so many lives.”

“The human killed me too,” Undyne continued, “But I came back.”

“I know,” Alphys said with a teary laugh, “I d-don’t know how you did it, but thank the stars.” Undyne thought the second part sounded like a lie but decided to let it go.

“I know how I did it,” Undyne said, “I thought of my friends. I thought of you.”

Alphys was quiet for so long that Undyne was afraid that the phone had disconnected. “I-I’m glad you thought of us, then,” Alphys said finally, “I-I can’t imagine l-l-losing you, Undyne.”

Everything was quiet once more save for the rumble of Mettaton’s rocket as the warm air around them cooled, signaling their entrance from Hotland into New Home. Undyne mused that by the end of the day, Alphys’s fears will probably come true, no matter how much she didn’t want to imagine it. Her chest ached, but it wasn’t from her wounds.

The secret she held about Alphys-Undyne berated herself for not confessing it earlier. If only Alphys had known how Undyne felt for a week, a day, even an hour before the human entered the Underground. She wasn’t sure if Alphys felt the same way, but at least when she died, Undyne wouldn’t be living a lie.

And what if she revealed her secret now? Alphys would be glad to know. But Undyne could only imagine how it would hurt to learn of her feelings now of all times. It would be unspeakable cruel. And Undyne would be unspeakably selfish for confessing.

But Undyne was dying in the arms of a narcissistic robot after saving the entire Underground from a sadistic murderer and successfully collecting the final human soul needed to free monsterkind. She could be a little selfish today, she decided. As a treat.

“Listen, Alphy,” Undyne said, trying to recall the dozens of letters she had written in the past but never wanted to send, “I’m really lucky to have met you. You’re smart beautiful and you care so much about everything. I’ve cherished every moment I’ve spent talking to you, and hanging out with you. And I wished I told you this earlier, but I could never find the right words.”

“U-undyne?” Alphys squeaked, “What are you saying?”

“I love you, Alphys,” Undyne said, “I don’t know when I started loving you, but it just happened and I never wanted to stop. And-“ she coughed, “-and I know it’s a bad time, and I understand if you don’t feel the same way, but I just wanted to get everything out of the way before…you know.”

“Undyne,” Alphys gasped, “O-oh my god, I-I-I feel the same. I’m sorry I never told you this be-before. I’m so sorry!”

“You’re right, darlings,” Mettaton interrupted, “This is awful timing.”

“This doesn’t involve you!” Undyne snapped, “Shut up!”

“Ah, good,” Mettaton said, “You’re getting your energy back.”

“M-m-mettaton,” Alphys stuttered before making a sound halfway between a laugh and a sob, “Mettaton, she said-she said-“

“She said exactly what I told you she’d say if you’d talked to her sooner, darling,” Mettaton scoffed. He paid no attention to the glare Undyne shot his way for getting Alphys to sniffle again. “Let’s save whatever lover’s reunion you’ll have to when we get to the king, shall we?” The roar of his engines grew louder as he dove over Asgore’s castle, en route to the royal gardens. “That is,” he said condescendingly, “if you can stay alive until then.”

“Is that a fucking challenge?” Undyne yelled, barely noticing the sharp pain in her ribs as she did. Mettaton gave a glamorous chuckle. The sound of Alphys’s hyperventilating switched between hysterical sobbing and giddy laughter every few seconds.

~

An orange light passed through the stained glass windows of the judgment hall. Beyond it, Undyne could see twilight shining through the barrier. It seemed her journey would be over soon.

Feeling Mettaton stop, she tried to see who was standing in front of him, grunting in frustration when her body wouldn’t move on its own. Then she heard a voice that she almost forgot she’d abandoned earlier that day in her own grief and anger, kneeling in front of a dust-covered scarf in the snowy fog.

“Whoa,” Sans said, “You guys…have that thing’s soul?”

“Yes,” Mettaton said, weirdly agitated, “Is the king here? We need to see him. Now!”

“Uh, he is,” Sans said. Undyne heard the soft taps of his footsteps grow closer. “Come on. I’ll take you.”

The golden light of the judgment hall was replaced by the green grass of the royal garden. Mettaton stumbled and sputtered out a “What the!?” Undyne wondered if she had passed out for a moment when Sans and Mettaton had walked through the judgment hall to the garden.

“Howdy!” Asgore called, “How can I-“ A watering can clattered to the ground and heavy footsteps hurried towards them.

A pair of furry arms around her replaced Mettaton’s cold, metallic ones and gently set Undyne onto the soft grass. Mettaton took the opportunity to produce the lunchbox containing the soul and toss it to Asgore, before turning to Sans, who was now pestering him about Alphys’s whereabouts.

Undyne blinked at the blurry visage of her mentor in front of her. He was examining her wounds, his hands glowing in preparation to heal.

“I did it, Asgore,” she said, her voice raspy, “I got a human soul. I stopped the human.”

Asgore opened his mouth to say something but grimaced and covered his mouth as tears slid down his face. “That is wonderful,” he said finally, “I am so proud of you.”

“C’mon, big guy,” Undyne gave Asgore the biggest grin she could manage. “Don’t cry. I’ll be okay.”

Asgore looked dejected as he ran a hand through Undyne’s hair. His other hand pressed against one of the wounds on Undyne’s stomach, but the soothing warmness that usually accompanied healing magic was gone.

“Hey,” she said, “Did you know I always thought of you as my dad? I used to tell kids at school that my dad was the king.”

Asgore laughed sadly. “I have always thought of you as my daughter,” he replied, “You know, so did Gerson. He talked to me about it.” At Undyne’s next rattled, labored breath, he placed a dust-stained hand over his eyes. “Please do not do this, Asri-Undyne,” he wept, “I cannot-I cannot do this again.”

Undyne frowned. “I’m sorry.”

“It is not your fault,” Asgore said, quickly wiping his eyes and pressing his hand to Undyne’s wounds again.

“UNDYNE!” Alphys’s voice rang through the garden, followed by Mettaton’s “Seriously, how did you do that?” Before Undyne could call Alphys’s name, the lizard was already kneeling beside her in the grass.

“Doctor,” Asgore said with a pain in his voice that Undyne dreaded, “her armor. It is fused to her body. What do I do?”

…What?

Undyne looked down and saw Asgore trying to pry away pieces of her broken chest plate, to no avail. Asgore seemed confused, but Alphys’s teary eyes were full of horrified recognition. Undyne suspected that if Mettaton hadn’t come up behind her at that moment to put his hand on her shoulder, the lizard wouldn’t have been able to do anything but cry.

“H-h-h-heal her th-through the-the armor,” Alphys said, “I-if-if we get h-her stabilized, we can-we can o-operate on her l-l-later.”

Asgore continued to heal the wounds on her chest and stomach, but Undyne couldn’t feel any of it. The unbearable pain from before was gone, leaving behind only a numb, floating sensation. The only thing she could feel was Alphys’s two hands squeezing her own. And the only things she could see were Alphys and Asgore’s tear-streaked faces, and a solemn, bony frown lurking behind them.

“I’m sorry about Papyrus,” Undyne said to Sans, who she was sure wasn’t beside her a second ago.

“I’m sorry too,” Sans sighed and turned away, disappearing a moment after.

Alphys was still squeezing her hand. With what little strength she had left, Undyne found Alphys’s thumb and squeezed back.

“I love you,” Alphys muttered again and again like a mantra. “I love you, Undyne. I-I-what am I going to d-do without you? I can’t-I can’t-“

“You’ll be fine,” Undyne managed, “You evacuated the entire Underground. You can do anything! And if you can’t, then Asgore and Mettaton can help you. And if they don’t, I’ll come back and haunt the shit out of them!”

Alphys choked out a laugh. “D-don’t say that.”

“Like that!” said Undyne, “Keep smiling like that, and don’t ever stop!” She tried to squeeze Alphys’s thumb again but realized she couldn’t feel where her own hand was.

From the edge of her vision, she saw Asgore frowning at his hand, which was covered in some kind of grey liquid. When he caught her looking, he quickly put his hand down, out of sight.

“Undyne,” Asgore said, giving her a resigned smile, “I would like to thank you for your services to monsterkind. As your king, I mean. I cannot wait to show you all the wonderful things on the surface. I know you will find it beautiful.”

Undyne couldn’t find the breath to laugh, so she settled for a contented sigh instead. “Aww, Asgore!” She tried to grin at him but found that her face was too numb. “I can’t wait to see the sun! And the stars, too. What do they look like?”

Asgore let the remaining tears slide down his cheek. “The stars and the moon are brighter than all the crystals in Waterfall,” he began, “And when the sun sets, the sky turns orange and pink. And when the sky turns purple-that’s when you can finally see all the stars.”

It was a description Undyne had heard many times before, both from Asgore himself and from Gerson. She didn’t know if the image she painted in her mind was accurate, but she supposed there was no way she would find out otherwise. 

She couldn’t feel Alphys’s hands anymore, but she closed her eyes and imagined that she was there anyway, and she could let go of her hand at any time and trust that it would be there when she returned. Papyrus and Sans would be at her side, and Mettaton would be at Alphys’s side. And Asgore would be behind her, reciting to her the names of every star that he had learned about as a child.

Undyne could sit there forever, watching the sunset with Alphys. And when dusk faded into twilight, she could lean her head onto Alphys’s shoulder and stay like this until the sun returned.

~

Three hours after the murderous human who rampaged through the Underground was defeated, the dust of a hero scattered across the garden of her king and, like water, seeped into the tangled roots of tenderly nurtured flowers. DETERMINATION had allowed her to change the course of fate for a few hours. But it was only for a few hours.

The king knelt; mourning for the child whose dust was spread across the garden. But the one who mourned with him the first time could never mourn for anything again.

The hero’s lover curled up in the grass as she silently cursed the human, cursed the laws of nature, and cursed herself. Eventually, she was carried home by her loyal friend. The Underground had fallen apart, and so had she. Someone would have to pick up the Underground’s pieces. And someone would have to pick up her pieces, too.

In the corner of the garden, a hooded figure watched, fingers running through red fabric. It was pitiful, but he couldn’t bring himself to feel the same grief for anyone else anymore.

Beside the king’s foot, covered by flower petals, was a plastic container set down and forgotten in the panic. Inside, a glowing red heart pulsated with energy and destroyed its plastic prison. The heart, unnoticed by all but the hooded figure, rose from the ground, twisting time and space around it until the world stuttered, and Undyne found herself watching Waterfall’s bridge again.

~

“You cannot give up just yet…”

“Chara! Stay DETERMINED…”

**Author's Note:**

> Yes Mettaton did lecture Undyne on the proper handling of souls and then yeet one to Asgore in a Tupperware container.
> 
> Idk I'm fascinated by the fallout of when the human gets killed by one of the bosses on a Genocide run. Pretty much all the characters (except Toriel and Asgore) show their best sides in this run (like I've got like 8 oneshots I want to write about everyone during Genocide that I'll probably never write), and the tragedy of Genocide is that all of the character development is for naught, since the human ends up killing everyone anyway. I love to explore what may happen if everyone's character development actually contributes to stopping the human. It's like the Queen Alphys ending where you can see how she's grown. I guess Undyne in this story dies anyway but hey. At least she got to be an anime hero!
> 
> (Oh and controversial opinion: Undyne the Undying is the sexiest Undertale boss. I love what they did with Sans but Undyne's whole shounen monologue and magic girl transformation? Battle Against A True Hero? Mwah.)
> 
> Please review! Constructive criticism is very welcome!


End file.
